First make the pasta. Blend the flour, eggs, olive oil and a pinch of salt in a processor, to fine crumbs. Tip onto a clean surface and lightly knead to bring together in a smooth dough ball. Wrap in cling film and refrigerate for 30 minutes.

2.

Next, make the tomato sauce. Heat a quarter of the oil in a large pan and add the tomatoes, onion, carrot, celery, and sugar and cook over a low heat for about 30 minutes, adding the remaining oil throughout this time, until the sauce reaches a thick consistency. Blend in a processor to a fine puree and pass through a fine sieve twice to give a smooth sauce. Reserve until ready to use, re-warming on serving.

3.

Meanwhile, make the mushroom mixture. Melt the butter in a large frying pan and soften the shallot and garlic for 2-3 minutes. Add the mushrooms and cook gently for about 10-15 minutes until the liquid has evaporated. Stir the parmesan through and season well. Leave to cool.

4.

To make the béchamel sauce, melt the butter in medium saucepan, add the flour and cook gently for 1 minute. Remove from the heat and add the milk and cream gradually, stirring all the time until all is incorporated. Return to a medium heat and stirring constantly, simmer until the sauce thickens and coats the back of the spoon. Season well.

5.

Cut the chilled pasta dough into four pieces. Pass one piece (covering the remaining pieces) through a pasta machine, starting with the widest setting. Reduce the setting each time the dough goes through until it reaches the thinnest setting and the dough is a long, thin and very smooth strip. Repeat until all of the dough pieces are used up, again covering any dough not being used.

6.

Bring a wide pan or roasting tin of salted water to a simmer and working in batches, blanch the pasta strips for 1 minute. Carefully remove and lay out on a damp tea towel without over lapping. Cover with cling film until ready to use. Repeat with the remaining pasta strips.

7.

Preheat the oven to 150C (300 F / Gas Mark 2). To assemble the lasagne, butter a 7” square, oven proof dish and line with a piece of greaseproof paper, leaving excess hanging over to use as ‘lifters’ later. Put a layer of pasta on the base (cutting the pasta strips to size), followed by a layer of the béchamel sauce and finally a layer of the mushroom mixture. Repeat the three layers until all the mixture is used up, and then finish with a layer of the béchamel on top. Sprinkle the gruyere cheese on top and bake in the oven for about 40 minutes.

8.

Using the greaseproof paper, lift the lasagne out of the dish carefully and onto a chopping board. Use a metal cutter to cut out four servings, lifting them onto the centre of each serving plate. Warm the tomato sauce through and spoon out in spots around the plate to encircle the lasagne. Garnish the top of the lasagne with rocket and freshly ground black pepper and serve.